Your mortgage payment is $1,896 a month — but in the first year, only about $300 of each payment actually pays down the loan. The rest is interest. That lopsided split surprises nearly every first-time buyer, and it is exactly what an amortization schedule reveals.

The HSH Amortization Calculator lays out any fixed-rate mortgage HSH-style: the monthly principal-and-interest payment, the lifetime interest cost, the payoff date, and a year-by-year schedule showing how each payment splits between interest and principal as the balance falls.

Use it when comparing loan offers, deciding between a 15- and 30-year term, or understanding what an extra payment each year would really save you.

What Does the HSH Amortization Calculator Do?

This calculator takes your loan amount, annual interest rate, loan term (10, 15, 20, or 30 years), and first payment date, then computes the fixed monthly payment covering principal and interest.

It also reports the total of all payments, the total interest over the life of the loan, the payoff date, and a scrollable year-by-year schedule with each year's interest paid, principal paid, and remaining balance.

How to Use the HSH Amortization Calculator

Enter the loan amount (the borrowed sum, not the home price), the annual interest rate as a percentage, and pick the loan term. Set the first payment month — it defaults to next month — so the payoff date and schedule align with reality.

Press Calculate. The headline is your monthly payment; the rows give lifetime totals; the schedule table shows the year-by-year breakdown. Reset clears the form.

The Monthly Payment Formula

A fixed-rate mortgage payment comes from the standard amortization formula. The formula is:

M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1)

where P is the loan amount, r the monthly rate (annual ÷ 12), and n the number of payments. For $300,000 at 6.5% over 30 years (n = 360, r = 0.005417): M = $1,896.20. The payment never changes — only its internal split does.

Why Early Payments Are Mostly Interest

Each month, interest is charged on the current balance: balance × monthly rate. Early on the balance is huge, so interest devours most of the payment — about $1,625 of the first $1,896 payment in the example above, leaving only ~$271 for principal.

As the balance shrinks, the interest slice shrinks with it and the principal slice grows. By year 20 of that same loan, over $1,400 of each payment attacks principal. The crossover — where principal exceeds interest — arrives around year 19. Nothing about your payment changed; the balance did.

Reading the Year-by-Year Schedule

Each schedule row shows one year: interest paid that year, principal paid, and the remaining balance at year's end. Scan the balance column to see equity building in slow motion — after 5 years on the example loan, you have paid $113,772 but the balance has fallen only about $24,000.

That gap shocks people, but it is the math working as designed: early payments rent the money more than they repay it. The schedule turns an abstract complaint into exact numbers you can plan around.

Worked Example: $300,000 at 6.5% for 30 Years

The classic American mortgage: $300,000 borrowed at 6.5% annual, 30-year term, first payment November 2026.

First: monthly rate. 0.065 ÷ 12 = 0.005417; payments n = 360.

Then: payment. $300,000 × 0.005417 × (1.005417)³⁶⁰ ÷ ((1.005417)³⁶⁰ − 1) = $1,896.20.

Then: lifetime cost. $1,896.20 × 360 = $682,633 total; minus $300,000 principal = $382,633 interest.

Answer: $1,896.20/month, $382,633 total interest, paid off October 2056. You pay more in interest than you borrowed.

Worked Example: Same Loan at 15 Years

$300,000 at 6.5% but over 15 years (n = 180).

First: payment. The formula gives $2,613.32 per month — $717 more than the 30-year.

Then: lifetime interest. $2,613.32 × 180 − $300,000 = $170,397.

Answer: $2,613.32/month with only $170,397 total interest — a $212,236 saving versus the 30-year, bought with a higher monthly payment. The schedule also shows principal dominating from roughly year 4.

Worked Example: The First-Year Split

Back to the 30-year example — where exactly does year one's $22,754 go?

First: month 1 interest. $300,000 × 0.005417 = $1,625; principal = $1,896.20 − $1,625 = $271.20.

Then: repeat 12 times as the balance ticks down. Year-one totals: about $19,318 interest and $3,437 principal.

Answer: 85% of year-one payments are interest. This is why extra principal payments early in the loan are so powerful — they attack the balance when interest is at its hungriest.

Worked Example: A Smaller Loan, 20-Year Term

$180,000 at 6.0% over 20 years (n = 240, r = 0.005).

First: payment. $180,000 × 0.005 × (1.005)²⁴⁰ ÷ ((1.005)²⁴⁰ − 1) = $1,289.57.

Then: totals. $1,289.57 × 240 = $309,496; interest = $129,496.

Answer: $1,289.57/month, $129,496 interest, paid off 20 years after the first payment. The 20-year term splits the difference: meaningful interest savings over 30 years without the 15-year's payment shock.

The True Cost: Interest Often Exceeds Principal

On a 30-year loan at 6.5%, total interest ($382,633) exceeds the amount borrowed ($300,000). The house costs $682,633 before taxes, insurance, and maintenance. This is not a rip-off — it is the price of spreading repayment over three decades.

Two levers cut it: a lower rate (even 0.5% saves tens of thousands) and a shorter term. Both appear instantly in the calculator — run your scenarios before you sign, not after.

What Amortization Does Not Include

This schedule covers principal and interest only. Your actual monthly check is usually larger: property taxes, homeowner's insurance, and possibly PMI (private mortgage insurance) ride along in escrow — the full PITI payment.

It also assumes a fixed rate and no extra payments. Adjustable-rate mortgages reset the math at each adjustment, and any extra principal payment shortens the schedule — the table shows the baseline, not the optimized path.

What One Extra Payment a Year Does

Paying one extra monthly payment per year — or a twelfth extra each month — attacks the balance when interest is hungriest. On the $300,000, 6.5%, 30-year example, that single extra payment yearly cuts the term by roughly 6 years and saves about $116,000 in interest.

The mechanism is pure amortization: every extra dollar goes 100% to principal, shrinking the balance that all future interest is computed on. Early in the loan, when $1,625 of each payment is interest, an extra $1,896 against principal does the work of months of regular payments.

Refinancing: Reading Two Schedules at Once

Refinancing decisions require two amortization schedules: the remaining years of your current loan versus the full term of the new one. A refinance from 6.5% to 5.75% with 25 years left, restarted at 30 years, can lower the payment while raising total interest — the longer new term quietly undoes the rate cut.

The honest comparison: total interest on the old schedule's remaining years plus closing costs, versus total interest on the new schedule. Run both in the calculator before signing — the monthly payment alone will mislead you nearly every time.

Common Amortization Mistakes

The biggest mistake is comparing loans by monthly payment alone — a lower payment over more years usually costs far more in total interest. Always compare the total-interest row.

Others: entering the home price instead of the loan amount (forgetting the down payment), assuming the payment includes taxes and insurance, and believing that paying biweekly "saves a fortune" — it helps, but the mechanism is just one extra payment a year, which you can see in the schedule's logic.

Where Amortization Schedules Are Useful

Homebuyers use them to choose between terms and to feel the true cost before committing. Refinancers compare the remaining schedule of the old loan against the full schedule of the new one — the only honest comparison.

Financial planners use them to weigh extra payments against investing, and tax preparers pull the annual interest figures for deduction planning. One table serves the buyer, the planner, and the accountant.

How to Interpret Your Result Correctly

Read the result as three layers: the monthly payment (can I afford this?), the total interest (what does this really cost?), and the schedule (when does my money start working for me?). The payment answers the budget question; the interest answers the wealth question.

Then remember the boundaries: P&I only, fixed rate assumed. Add your tax, insurance, and PMI estimates for the true monthly number, and treat the schedule as the plan you will beat with extra payments — not the plan you must accept.

Frequently Asked Questions

1. What is mortgage amortization?

The gradual repayment of a loan through fixed monthly payments, where each payment splits between interest (on the current balance) and principal. Early payments are mostly interest; later ones mostly principal.

2. How is the monthly payment calculated?

With M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), where P is principal, r the monthly rate, n the number of payments. The calculator applies it instantly for any term.

3. Why is so little of my early payments principal?

Because interest is charged on the full balance each month. On $300,000 at 6.5%, month one's interest alone is $1,625 of the $1,896 payment. The principal share grows as the balance falls.

4. When does principal exceed interest in my payment?

Around year 19 on a 30-year loan at 6.5%; around year 4 on a 15-year. Higher rates and longer terms push the crossover later — check your schedule's yearly splits.

5. Is a 15-year mortgage always better than a 30-year?

It saves enormous interest — $212,236 in the worked example — but demands a much higher payment. Better if the payment fits comfortably; a stretched 15-year that risks default is worse than a comfortable 30-year with extra payments.

6. Does the calculator include property tax and insurance?

No — principal and interest only. Your real payment adds taxes, insurance, and possibly PMI (the full PITI). Add those estimates separately for the true monthly figure.

7. What happens if I make extra principal payments?

They reduce the balance directly, which cuts all future interest and shortens the loan. Extra payments early in the term save the most, since that is when interest is hungriest.

8. Can I use this for an adjustable-rate mortgage?

Only for the fixed-rate portion. ARMs reset the rate (and the math) at each adjustment date, so a single schedule cannot cover the whole loan.

9. What is the payoff date based on?

Your first-payment month plus the full term: November 2026 plus 360 payments ends October 2056. Extra payments or rate changes move it earlier or later.

10. Why does total interest exceed the loan amount?

Thirty years of interest on a large balance compounds enormously. At 6.5%, the $300,000 example accrues $382,633 in interest — the cost of three decades of borrowed money.

11. Should I enter the home price or loan amount?

The loan amount — price minus down payment. Entering the price overstates the payment and the interest, sometimes dramatically.

12. How do I compare two refinance offers?

Compare total interest over the time you will actually hold the loan, plus closing costs — not just the monthly payment. A lower rate with high fees can lose to a higher rate with no fees on a short hold.

13. What is negative amortization?

When payments do not even cover the interest, so the balance grows. Standard fixed-rate mortgages never do this — but some payment-option ARMs can. This calculator models only standard amortization.

14. Does paying biweekly really help?

Modestly: biweekly payments equal 26 half-payments = 13 full payments a year, i.e., one extra payment annually. It shortens a 30-year loan by about 4 years — real savings, but no magic.

15. Where does HSH fit into mortgage shopping?

HSH Associates has published mortgage rate data and amortization tools for decades; shoppers use its rate tables to benchmark offers. Whatever source you use, run the full amortization before signing — the schedule never lies.